With a known method of this type disclosed by German Offenlegungsschrift No. 16 53 264 for gluing and impregnating of wood chips and the like, the chips by way of conveyor belts come free-falling into a conical funnel which opens into a mixing container that is larger in diameter than that of the funnel. The chips fall into the mixing container without mechanical engagement with rotating parts until reaching a mixing tool located at the container bottom; the mixing tool is provided for example in the shape of a centrifugal disc or plate and the chips along this path pass through a downwardly directed spray cone generated in the middle of the container. The centrifugal disc or plate, supported by particularly embodied blades, scoops and the like move the chip flow which has fallen through the glue-spray-cone along the walls of the cylinder in a flow upwardly again circulating around the middle downward flow of the chips, whereby chips not yet coated or covered with glue prior to entry thereof into an upwardly located tangential discharge or outlet can come again with the central incident or oncoming chip cone or funnel downwardly in the region of the central downwardly directed glue-spray-cone.
Disadvantageous with this known approach is that the vertical mixing container must have such a large diameter that the glued chips passing from the bottom of the mixing container helically or spirally to the upper outlet do not influence the chip funnel dropping downwardly within this external flow. Furthermore, there exists the disadvantage that the chips are destroyed during reversal thereof by 180.degree., particularly upon impinging against the fast rotating centrifugal plate or disc and the conveying tools thereof. With the known machine accordingly chip destruction arises as such destruction had to be encountered and accepted with the known and previously horizontally located fast rotating gluing machines with which the chip material must be reversed or diverted from the vertical into a horizontal direction by entry, feeding or drawing- taking-in blades. The mixing tools, particularly the diverting or reversing blades located in the diverting or reversing location of the chip flow heat up relatively strongly as a consequence of the friction and braking of the chips encountered therewith. The consequence is a rapid wear of these diverting or reversing tools as well as a rapid wearing-off of the drum in the region of the diverting or reversing zone.
The main disadvantage lies in the chip destruction itself aside from the wear which is not inconsiderable or unimportant. The chip destruction has as a consequence a reduction of the transverse and bending strength (ultimate tensile strength or tenacity) for the finished chip panel or plate as well as a considerably greater glue consumption, since the glue consumption is greater to an extent commensurate with the smaller the glue particles are respectively therewith.
An object of the present invention accordingly is to create a gluing method or gluing machine with which the incoming chips without positive reversal or diverting thereof out of the incoming direction are subjected to an optimum gluing and glue distribution in a direction vertical or opposite thereto without shock, impact or surge stress, and with a minimum heating by friction. A gluing machine suitable for carrying out this method is to assure a high chip capacity or through-passage with smallest possible chip destruction during an economical gluing with nominal space requirement.